Earnings per share (Tables)

6 Months Ended

Jun. 30, 2012

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

			Three Months Ended				Six Months Ended
			June 30,				June 30,
(Amounts in thousands, except share and per share amounts)			2012		2011		2012		2011
	Net income attributable to common
		stockholders – basic and diluted	$	18,892	$	20,157	$	38,374	$	38,364
	Weighted average shares outstanding – basic and diluted			5,107,415		5,106,351		5,107,199		5,106,144
	Net income per common share – basic and diluted		$	3.70	$	3.95	$	7.51	$	7.51